#define _CRT_SECURE_NO_WARNINGS 1
#include <stdio.h>
int main()
{
    int a, b, c, d;
    scanf("%d %d %d %d", &a, &b, &c, &d);
    int max = a;
    if (max < b)
        max = b;
    if (max < c)
        max = c;
    if (max < d)
        max = d;
    printf("%d", max);
    return 0;
}